In a conventional radar system, discrete transmission radars transmit transmission signals of different center frequencies for which intrapulse frequency modulation is performed upwardly, as disclosed in, for example, Nonpatent Literature 1. A reception radar receives the transmitted signals that are reflected by a target as reception signals. Then, under the assumption that no influences are caused by the Doppler frequency by the target, the reception signals having different center frequencies, i.e., reception signals in different bands are separated, the reception signals are multiplied by a window function to suppress sidelobes occurring due to the cross correlation between the reception signals of different bands, and integration (synthesis) is performed.
According to such a conventional radar system described above, under the assumption that there is no influence of the Doppler frequency of a target, the reception signals having the different center frequencies can be integrated coherently, high range resolution can be provided, and sidelobes occurring due to the cross correlation can be suppressed by multiplying the reception signals by window functions.